Elastomeric universal rotor hub

Abstract

This invention is directed to helicopter rotor hubs which includes an elastomeric material between an inner and outer hub. The inclusion of elastomeric material transmits torque, thrust and in-plane loads and is flexible in the tilt direction.

What is claimed and desired to be secured by Letters Patent of the United States is: 
     
       1. An elastomeric universal rotor hub which comprises: an inner hub having an axis and adapted to be connected to a rotor shaft for rotation about said axis, said inner hub including a cylindrical section and radially disposed teeth extending outwardly from the cylindrical section;   an outer hub coaxial with said inner hub, said outer hub including a circular ring and radially disposed teeth extending inwardly from said ring between said inner hub teeth, respectively;   an elastomeric material interposed between said inner hub teeth and said outer hub teeth;   an annular flange connected to said inner and outer hubs; and   a further elastomeric material interposed between the annular flange and one of said inner and outer hubs, and comprising part of the connection of the annular flange to said inner and outer hubs.   
     
     
       2. An elastomeric universal rotor as claimed in claim 1 in which said elastomeric material interposed between said inner hub teeth and said outer hub teeth is at least one thin strip of material. 
     
     
       3. An elastomeric universal rotor as claimed in claim 2, in which said elastomeric material interposed between said inner hub teeth and said outer hub teeth is threaded between the inner and outer ends of said teeth between the ends of said teeth and the respective hubs. 
     
     
       4. An elastomeric universal rotor as claimed in claim 3, in which said elastomeric material includes a pair of rubber strips which are threaded alternately above and below said teeth of said inner and outer hubs. 
     
     
       5. An elastomeric universal rotor hub as claimed in claim 1, in which said elastomeric material interposed between said inner hub teeth and said outer hub teeth includes rollers. 
     
     
       6. An elastomeric universal rotor as claimed in claim 5, in which said rollers are secured in their position between said teeth by a non-extensible material. 
     
     
       7. An elastomeric universal rotor as claimed in claim 5, wherein said non-extensible material is wire. 
     
     
       8. An elastomeric universal rotor hub, which comprises: an inner hub having an axis and adapted to be connected to a rotor shaft for rotation about said axis;   an outer hub connected to the inner hub for rotation therewith and for limited motion with respect to the inner hub about a pivot point on said axis; and   elastic means for connecting the inner and outer hubs;   said inner hub including a cylindrical section,   radially disposed teeth extending outwardly from the cylindrical section, and   at least one semispherical surface equidistant from said pivot point;     said outer hub including a circular ring extending about the inner hub cylindrical section,   radially disposed teeth extending inwardly from said ring between said inner hub teeth, and   at least one semispherical surface, concentric and co-extensive with said at least one inner hub semispherical surface, respectively; and     said elastic means including first elastomeric material interposed between said inner hub teeth and said outer hub teeth, and   second elastomeric material interposed between each pair of concentric and co-extensive semispherical surfaces of the inner and outer hubs.     
     
     
       9. A rotor hub, as described in claim 8, wherein: the inner hub comprises inner surfaces including said at least one inner hub semispherical surface, which define an axial compartment having at least one opening thereto;   the outer hub comprises a center portion which is disposed within said axial compartment and which includes said at least one outer hub semispherical surface, and   connecting means, extending through said at least one opening of the inner hub axial compartment, for connecting the center and ring portions of the outer hub.     
     
     
       10. A rotor hub, as described in claim 9, wherein: the at least one inner hub semispherical surface includes a top axial semispherical surface which forms a top surface of the inner hub axial compartment, and   a bottom axial semispherical surface which forms a bottom surface of the inner hub axial compartment;     the at least one opening to the inner hub axial compartment comprises a plurality of vertical slots which extend through side walls of the inner hub axial compartment;   the outer hub center portion is embodied as a sphere whose center coincides with said pivot point;   the connecting means comprises a like plurality of rods connected between said sphere and said ring and extending through the plurality of vertical slots, respectively; and   the second elastomeric material comprises a top elastomeric material bonded to the inner hub top axial semispherical surface, and   a bottom elastomeric material bonded to the inner hub bottom axial semispherical surface.     
     
     
       11. A rotor hub, as described in claim 10, wherein: the inner hub further comprises a bottom flange; and   the elastic means further comprises a ring of elastomeric material disposed between the bottom flange and the teeth of the inner and outer hubs.